Database for accidents and incidents in the fuel ethanol industry

The purpose of the present research is to collect information about accidents and incidents that have occurred at fuel ethanol facilities from 1998 to October 2014, and to keep complete unified records of them in a database. The developed database contains general information about the accident or incident, its sequence, mitigation measures, its causes and consequences for humans, environment and for the plant. Until now, this information is not available. The work consisted in gathering information from different documental sources and subsequent organization in a database. It complements the previous work made for biodiesel industry and fills the existing gap in the field of ethanol. Knowledge about this information enables us to manage plant risks, since the accidents that are more likely to occur and the main sources of risk can be easily identified. Also, it makes it possible to exchange information with interested third parties. Statistical analysis shows that accident frequency has an oscillatory behavior, rising in the last year. Fire is the most common type of accident, while equipment mechanical failure is the main cause of accident. Partial material loss has been identified as the most common consequence. Finally, some conclusions are obtained concerning to the importance of having an updated and complete accident and incident database.     

Method to analyze the regional life loss risk by airborne chemicals released after devastating earthquakes: A simulation approach

Widespread chemical plants render human life more vulnerable to major natural disasters such as earthquakes. Recognizing the potential cascading threats initiated by a devastating earthquake, a general methodology for assessing the life loss risks introduced by airborne hazardous chemical dispersion following seismically induced chemical release (SICR) was proposed. With a 600 km × 600 km region in North China as a demonstrative study area, the dispersion of ammonia released from multiple relevant chemical plants that were supposed to be damaged by a devastating earthquake was simulated in a probabilistic manner. Using an ammonia toxicity-fatality relationship and its toxicity concentration threshold, regional life loss and spatial spread were evaluated. The life loss risk was found to be non-prominent but would be very contingent on unfavorable meteorological conditions. Non-parametric correlation analysis revealed that the respective effects of meteorological mixing parameters on the risk exhibit new features in a disaster context, that is, stronger mixing would cause elevation of risk in a region. This preliminary research implied that the risk of chemical-induced life loss after a devastating earthquake deserves attention and a thorough uncertainty evaluation in the future.     

Predicting the aquatic risk of realistic pesticide mixtures to species assemblages in Portuguese river basins

Although pesticide regulatory tools are mainly based on individual substances, aquatic ecosystems are usually exposed to multiple pesticides from their use on the variety of crops within the catchment of a river. This study estimated the impact of measured pesticide mixtures in surface waters from 2002 and 2008 within three important Portuguese river basins (‘Mondego’, ‘Sado’ and ‘Tejo’) on primary producers, arthropods and fish by toxic pressure calculation. Species sensitivity distributions (SSDs), in combination with mixture toxicity models, were applied. Considering the differences in the responses of the taxonomic groups as well as in the pesticide exposures that these organisms experience, variable acute multi-substance potentially affected fractions (msPAFs) were obtained. The median msPAF for primary producers and arthropods in surface waters of all river basins exceeded 5%, the cut-off value used in the prospective SSD approach for deriving individual environmental quality standards. A ranking procedure identified various photosystem II inhibiting herbicides, with oxadiazon having the relatively largest toxic effects on primary producers, while the organophosphorus insecticides, chlorfenvinphos and chlorpyrifos, and the organochloride endosulfan had the largest effects on arthropods and fish, respectively. These results ensure compliance with European legislation with regard to ecological risk assessment and management of pesticides in surface waters.     

Risk assessment of Giardia from a full scale MBR sewage treatment plant caused by membrane integrity failure

Membrane bioreactors (MBR) are highly efficient at intercepting particles and microbes and have become an important technology for wastewater reclamation. However, many pathogens can accumulate in activated sludge due to the long residence time usually adopted in MBR, and thus may pose health risks when membrane integrity problems occur. This study presents data from a survey on the occurrence of water-borne Giardia pathogens in reclaimed water from a full-scale wastewater treatment plant with MBR experiencing membrane integrity failure, and assessed the associated risk for green space irrigation. Due to membrane integrity failure, the MBR effluent turbidity varied between 0.23 and 1.90 NTU over a period of eight months. Though this turbidity level still met reclaimed water quality standards (≤5 NTU), Giardia were detected at concentrations of 0.3 to 95 cysts/10 L, with a close correlation between effluent turbidity and Giardia concentration. All β-giardin gene sequences of Giardia in the WWTP influents were genotyped as Assemblages A and B, both of which are known to infect humans. An exponential dose-response model was applied to assess the risk of infection by Giardia. The risk in the MBR effluent with chlorination was 9.83 × 10^-3, higher than the acceptable annual risk of 1.0 × 10^-4. This study suggested that membrane integrity is very important for keeping a low pathogen level, and multiple barriers are needed to ensure the biological safety of MBR effluent.     

关于老工业区污染场地管理的探讨

根据在某老工业区第1批28块场地环境调查的实践,对污染场地管理中存在的问题进行了分析并提出了相应改进建议：①获取准确的场地资料难度很大,建议研究制定场地全过程档案管理制度;②工业企业关闭搬迁会产生新的环境污染风险,工业企业关闭搬迁应该成为污染场地管理的重要环节,环保部门应该在工业企业搬迁前介入,严格监管整个过程中的环境污染;③大量区域由于其中污染严重、风险高的场地缺乏修复资金而难以再开发利用,建议结合规划优先启动资金投入低的污染较轻区域修复,并同时对风险较高的污染场地进行风险管控,当区域开发取得一定规模、成就和收益后,可以整合资金力量和资源开展污染较重区域的修复。     

焦化行业环境风险预测应用

以焦化行业中典型企业——徐州某焦化生产企业年产100万t捣固焦生产线项目为例,采用新的评价体系和数学模式对项目环境风险进行定量的预测评价,在环境风险定量预测方面作出了有益的尝试,对同类焦化行业环境风险预测及防范具有很好的借鉴意义.     

Models-as-usual for unusual risks? On the value of catastrophic climate change

We study the role of intertemporal preference representations in a model of economic growth, stock pollutant and endogenous risk of catastrophic collapse. We contrast two polar instances of risk-sensitive preferences: the traditional “discounted utility” model, which imposes a positive rate of pure time preference and risk neutrality with respect to intertemporal utility, and multiplicatively separable preferences, which display risk aversion in that dimension but no pure time preferences. We show that both representations of preferences can rationalize the same economy when there is no collapse risk associated with pollution. Once we introduce a collapse risk whose hazard rate depends on the pollution stock, multiplicatively separable preferences are associated with a much higher value of catastrophic risk reduction, and a more stringent policy response. A relatively high discount rate may thus be compatible with large emissions abatement in the face of a low probability large impact event, reflecting preferences for catastrophic risk reduction.     

Risk assessment of safety level in university laboratories using questionnaire and Bayesian network

Accidents in university laboratories not only create a great threat to students’ safety but bring significant negative social impact. This paper investigates the university laboratory safety in China using questionnaire and Bayesian network (BN) analysis. Sixteen influencing factors for building the Bayesian net were firstly identified. A questionnaire was distributed to graduate students at 60 universities in China to acquire the probability of safe/unsafe conditions for sixteen influencing factors, based on which the conditional probability of four key factors (human, equipment and material, environment, and management) was calculated using the fuzzy triangular theory and expert judgment. The determined conditional probability was used to develop a Bayesian network model for the risk analysis of university laboratory safety and identification of the main reasons behind the accidents. Questionnaire results showed that management problems are prominent due to insufficient safety education training and weak management level of management personnel. The calculated unsafe state probability was found to be 65.2%. In the BN analysis, the human factor was found to play the most important role, followed by equipment and material factor. Sensitive and inferential analysis showed that the most sensitive factors are personnel incorrect operation, illegal operation, and experiment equipment failure. Based on the analysis, countermeasures were proposed to improve the safe management and operation of university laboratories.     

A thermal hazard risk evaluation of emulsion polymerisation and vinyl acetate monomers in the latex manufacturing process

Latex is extensively used in industrial products. However, completing some processes at scale leads to unacceptable levels of risk that need to be quantified and mitigated. Systemic risks must be eliminated wherever possible, and safety takes priority over efficiency and quality. To assess the process risks accurately, four raw materials were examined in this study: polyvinyl acetate (PVA), latex process-initiator-ammonium persulfate (APS) and hydrogen peroxide (H₂O₂), and vinyl acetate monomer (VAM). The physicochemical composition of the PVA latex process was determined via calorimeters, including differential scanning calorimetry (DSC) and vent sizing package 2 (VSP2). The calorimetry results showed that the protective colloid was a critical component in the polymerisation reaction. In addition, when adding initiators to the system, it is vital to observe the normal ratio of materials and keep the stirring system operating. The scenario system also simulated the effects of shutting down various inhibitory programs, including the build-up of free radicals that could result in a runaway reaction when the initiator was added in excess. On the other hand, the result of the risk matrix displayed as a medium level, indicating that although the probability of an accident is low, the resulting severity is at disaster level. As a result, this study provides process safety engineers with a reliable frame of reference for assessing the potential dangers in the PVA latex manufacturing process.     

Simulation of scenario characteristics of LPG tank explosion accident and its contribution to emergency planning: A case study

Leakage and explosion of hazardous chemicals during road transportation can cause serious building damage and casualties, and adoption of highly-efficient emergency rescue measures plays a critical role in reducing accidental hazards. Considering a liquefied petroleum gas (LPG) transport tanker explosion accident that occurred in Wenling, Zhejiang Province, China on June 13, 2020 as example, this study proposes a risk assessment framework. This framework recreates the leakage and explosion of the accident process using FLACS v10.9, suggests plans for evacuation, describes the rescue areas of different levels, and explores the influence of environmental factors on the evacuation and rescue areas. The results show that simulated and predicted distributions of fuel vapour cloud concentration and explosion overpressure can provide a reference basis for rapid rescue activities; the characterization of the dynamic effects of wind speed, wind direction, and temperature with respect to the evacuation and rescue areas can be used as theoretical support for on-site adjustment of rescue forces. The role of obstacles can prevent the expansion of the evacuation areas under low wind-speed conditions, and the presence of highly congested obstacles determines the level of the rescue area. The results obtained are important for the risk analysis and the development of emergency rescue measures in case of explosion accidents associated with transportation of hazardous chemicals on high-hazard and high-sensitive road sections.